Strip away type arguments from tagged templates when emitting.

src/compiler/factory.ts

@@ -1032,17 +1032,19 @@ namespace ts {
             : node;
     }
 
-    export function createTaggedTemplate(tag: Expression, template: TemplateLiteral) {
+    export function createTaggedTemplate(tag: Expression, typeArguments: NodeArray<TypeNode>, template: TemplateLiteral) {
         const node = <TaggedTemplateExpression>createSynthesizedNode(SyntaxKind.TaggedTemplateExpression);
         node.tag = parenthesizeForAccess(tag);
+        node.typeArguments = typeArguments;
         node.template = template;
         return node;
     }
 
-    export function updateTaggedTemplate(node: TaggedTemplateExpression, tag: Expression, template: TemplateLiteral) {
+    export function updateTaggedTemplate(node: TaggedTemplateExpression, tag: Expression, typeArguments: NodeArray<TypeNode>, template: TemplateLiteral) {
         return node.tag !== tag
+            || node.typeArguments !== typeArguments
             || node.template !== template
-            ? updateNode(createTaggedTemplate(tag, template), node)
+            ? updateNode(createTaggedTemplate(tag, typeArguments, template), node)
             : node;
     }
 

src/compiler/transformers/ts.ts

@@ -502,6 +502,9 @@ namespace ts {
                 case SyntaxKind.NewExpression:
                     return visitNewExpression(<NewExpression>node);
 
+                case SyntaxKind.TaggedTemplateExpression:
+                    return visitTaggedTemplateExpression(<TaggedTemplateExpression>node);
+
                 case SyntaxKind.NonNullExpression:
                     // TypeScript non-null expressions are removed, but their subtrees are preserved.
                     return visitNonNullExpression(<NonNullExpression>node);
@@ -2547,6 +2550,14 @@ namespace ts {
                 visitNodes(node.arguments, visitor, isExpression));
         }
 
+        function visitTaggedTemplateExpression(node: TaggedTemplateExpression) {
+            return updateTaggedTemplate(
+                node,
+                visitNode(node.tag, visitor, isExpression),
+                /*typeArguments*/ undefined,
+                visitNode(node.template, visitor, isExpression));
+        }
+
         /**
          * Determines whether to emit an enum declaration.
          *

src/compiler/visitor.ts

@@ -478,6 +478,7 @@ namespace ts {
             case SyntaxKind.TaggedTemplateExpression:
                 return updateTaggedTemplate(<TaggedTemplateExpression>node,
                     visitNode((<TaggedTemplateExpression>node).tag, visitor, isExpression),
+                    visitNodes((<TaggedTemplateExpression>node).typeArguments, visitor, isExpression),
                     visitNode((<TaggedTemplateExpression>node).template, visitor, isTemplateLiteral));
 
             case SyntaxKind.TypeAssertionExpression: